Anatomic set of mechanical models for the organ of Corti

A new model for the mechanical and hydrodynamical processes in the organ of Corti (OoC) is proposed. In this model the motion of the basilar membrane is provided as input, and we concentrate on the other components of the OoC. The model consists of a set of euations, all based on Newton’s laws, describing the motions and mutual interactions of the outer hair cells, the outer hair bundles, Deiter cells, the reticular lamina, Hensen cells, and the inner hair bundle. In addition, the model includes the equations describing the endolymph fluid motion in the subtectorial channel. Key ingredients in the model are the nonlinear constitutive laws governing the vibrations of the outer hair bundles and outer hair cells. The inner hair bundle oscillates via interaction with the endolymph flow. It is shown that under a minimal set of assumptions, and using basic mechanical principles, the components of the OoC listed above can act as a second filter, along with the basilar membrane filter, that enhances frequency selectivity, amplitude compression and signal to noise ratio. Significance Statement The organ of Corti (OoC) transfers vibrations in the inner ear to the auditory nerve, while amplifying, filtering, and adapting them. In spite of decades of intense study, there is no full consensus on its mechanical activity. While most of the work on the OoC concentrates on the basilar membrane (BM), we consider the BM’s vibration as given input, and provide a platform that enables testing the influence of possible models for each of its components on the performance of the OoC. The present set of models could explain the high frequency selectivity, amplitude compression, and signal/noise ratio of the OoC.